反应详情

To a stirred solution of histidine (3.17 g, 20.0 mmol) and sodium carbonate (2.23 g, 21 mmol) in 50 mL of water is added N-carboethoxyphthalimide (4.52 g, 20.0 mmol). After 1.5 hour, the reaction slurry is filtered. The filtrate is stirred and the pH adjusted to 1-2 with 4N hydrochloric acid. The resulting slurry is filtered and the solid washed with water and dried in vacuo (60° C., <1 mm) to afford 3.65 g (64%) of 2-phthalimido-3-(imidazol-4-yl)propionic acid as a white powder: mp 280°-285° C.; 1H NMR (DMSO-d6, 250 M Hz) δ 12.5 (br s, 1H), 7.90-7.60 (m, 6H), 6.80(s, 1H), 4.94 (t, 1H, J=7.8), 3.36 (d, 2H, J=7.8); 13C NMR (DMSO-d6) δ 170.1, 167.1, 134.8, 134.6, 133.2, 131.1, 123.2, 116.3, 52.4, 25.8; Anal. Calculated for C14H11N3O4. Theoretical: C, 58.95; H, 3.89; N, 14.73. Found: C, 58.80; H, 3.88; N, 14.66.

1. filtrationthe reaction slurry is filtered
2. filtrationThe resulting slurry is filtered
3. washthe solid washed with water
4. customdried in vacuo (60° C., <1 mm)